Trusses, Joists and Rafters
Victorian builders made the roof's skeleton primarily from wood---especially Oregon pine, white spruce, hemlock and English oak---although they also used structural steel and wrought iron near the end of the Victorian period.
Over the rafters and under the roof top, contractors placed roofing felt---made of hair mixed with asphalt---or sheathing paper. They also covered knot holes in the rafters with galvanized iron or tin to ensure a smooth layer beneath metal roofs.
For flat roofs, Victorian builders placed five layers of roofing felt on the rafters, followed by a coat of cement, topped with a layer of gravel---also called slag. They also covered flat roofs with various types of metal, including tin, zinc, lead, copper and corrugated iron.
Victorian builders most commonly used wood---fine cypress, redwood or cedar or lesser-quality pine or spruce---or slate shingles---typically blue, red, green, black, gray or purple---on sloped roofs. They also used tin, copper, zinc or milled lead sheets---especially for porch roofs---and fired clay tiles---often in a reddish-brown color.
To prevent leaky roofs, the builders lined any joints, angles and projecting elements, such as chimneys, walls and skylights, with flashing---or metal pieces made of tin, zinc, copper or lead.
Builders added purely decorative cast-iron roof cresting---spikes, spindles and other elements---along roof peaks to make the roofs seem even taller.